JP4400577B2 - AC generator for brushless vehicles - Google Patents

Description

  The present invention relates to an AC generator for a brushless vehicle mounted on a truck, a construction machine, an agricultural machine, or the like.

  In recent years, passenger car manufacturers and truck manufacturers have improved engines in order to comply with exhaust gas regulations, and accordingly, ambient temperatures of components mounted on the engine tend to be higher. In addition, the trend of demanding devices for ensuring safety, additional power sources, and comfort has been increasing year by year, and the load on vehicle generators has increased. In addition to the brushed structure that is mounted on passenger cars, the structure of the generator for vehicles is mounted on long-distance trucks with long operating hours and travel distances, and on construction machinery and agricultural machinery used in adverse environments with dust. Although it can be classified as a brushless structure with a long service life, especially in North American long-distance trucks, buses, and construction machinery, a brushless structure vehicle generator that can handle the above ambient temperature rise and obtain high output. Is required.

  Known technologies for obtaining high output include increasing the outer diameter of the stator and increasing the stack thickness, and reducing the resistance of the stator windings. Since the amount of heat generated in the device increases, the temperature rise of the rectifier becomes significant.

Some conventional vehicle generators include an auxiliary rectifier diode that obtains an exciting current in addition to a main rectifier diode that obtains an output current (see, for example, Patent Document 1). In this vehicular generator, auxiliary rectifying diodes are arranged on the upper surface or the lower surface of the radiating fins constituting the rectifying device.
JP 60-109748 A (page 1-3, FIG. 1-4)

  By the way, as described above, when the temperature of the rectifier rises as the output of the vehicle generator increases, the temperature of the auxiliary diode (auxiliary rectifier diode) disposed close to the upper surface or the lower surface of the radiation fin increases. There was a problem. This is because the auxiliary diode itself used for obtaining the exciting current generates a small amount of heat but receives radiant heat from the radiation fin. In addition, brushless vehicle AC generators for North America are classified into two mounting types, and the stay dimensions are standardized. For this reason, the size in the radial direction is limited, and since the distance between the bearing holding the rotor and the stator or the rectifier approaches, there is a problem that the temperature of this bearing also increases significantly. It was. From the above, even when the brushless structure is adopted, it is difficult to achieve the original purpose of extending the life due to the temperature rise of the auxiliary diode and the bearing accompanying the increase in output.

  As countermeasures, there are known techniques such as increasing the air volume and wind speed of the cooling fan, but the cooling fan provided in the brushless vehicle generator cannot increase the outer diameter due to the aforementioned dimensional restrictions in the radial direction. Even if the number of sheets or the area in the axial direction is increased, there is a possibility that the strength of each fan blade may be reduced, so these measures are limited, and the wind speed and air volume cannot be increased as expected.

  The present invention has been created in view of the above points, and an object of the present invention is to provide a brushless vehicle AC generator capable of reducing the temperature of an auxiliary diode and a bearing and realizing a long life. There is.

  In order to solve the above-described problems, a brushless vehicle AC generator according to the present invention supplies a stator having a stator winding, a rotor disposed opposite to the inner periphery of the stator, and the rotor. Rectifying the output voltage of the field winding that generates magnetic flux, the stator winding and rectifying the output voltage of the stator winding, and supplying the exciting current to the field winding by rectifying the output voltage of the stator winding A rectifier having an auxiliary diode, a bearing that rotatably holds the end of the rotating shaft of the rotor, and a rear cover having a plurality of intake holes that protect the electrical components including the rectifier and introduce cooling air The auxiliary diode is disposed between the bearing and the rear cover along the rotation axis of the rotor. In the case of the brushless structure, a brush device arranged so as to cover the end of the rotating shaft of the rotor becomes unnecessary, so that it becomes possible to arrange an auxiliary diode in this empty space, and from the radiating fin of the rectifying device The temperature of the auxiliary diode can be reduced by separating it, and the life of the auxiliary diode can be extended with the temperature reduction.

  Moreover, it is desirable that the above-described auxiliary diode is disposed at a position on the inner peripheral side of the radiating fin to which the rectifying element is joined and in which the circumferential position does not overlap. Thereby, it becomes possible to prevent the influence of the direct heat damage to the auxiliary diode due to the heat radiation from the surface of the radiation fin.

  Further, it is desirable that some of the plurality of intake holes described above are formed at positions corresponding to the auxiliary diodes along the rotation axis of the rotor. As a result, low-temperature cooling air sucked from the outside and not used for cooling other members can be directly applied to the auxiliary diode and the bearing, and these temperatures are surely reduced and a long life is realized. It becomes possible.

  Further, the rectifier described above has a radiation fin to which the rectification element is joined, a metal terminal for performing electrical wiring of the rectification element and the auxiliary diode, and a partition portion that blocks heat radiation from the radiation fin to the auxiliary diode. It is desirable to provide the terminal block formed in the circumference | surroundings. Specifically, it is desirable that the partition wall described above has a concave shape, and an auxiliary diode is disposed inside the partition wall. As a result, it is possible to reliably block the heat radiation from the radiating fin to the auxiliary diode by the partition wall, and to guide the cooling air to the auxiliary diode and the bearing along the partition wall, thereby reliably reducing these temperatures. Is possible.

  The rear cover described above preferably includes an intake introduction guide wall that guides cooling air introduced from the outside to the auxiliary diode. As a result, only low-temperature cooling air that is sucked in from the outside and is not used for cooling other components can be separated and directly applied to the auxiliary diode or bearing, and these temperatures can be reliably reduced. become.

  Hereinafter, an AC generator for a brushless vehicle according to an embodiment to which the present invention is applied will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing the overall structure of a brushless vehicle AC generator according to an embodiment. FIG. 2 is a rear view showing the overall structure of the brushless vehicle AC generator according to one embodiment.

  As shown in FIGS. 1 and 2, the brushless vehicle AC generator 1 of this embodiment includes a stator 2, a rotor 3, a field winding 4, a front housing 51, a rear housing 52, a rectifier 6, and a regulator. 7, a rear cover 8 and the like.

  The stator 2 serves as an armature, and a stator winding 22 is wound around the stator core 21. The rotor 3 functions as a field, and is disposed opposite to the inner peripheral side of the stator 2. This rotor 3 includes claw-shaped magnetic pole portions formed by rotating yoke portions 32 and 33 that rotate together with the rotating shaft 31, claw-shaped magnetic pole portions 34 that are formed integrally with the rotary yoke portion 33, and a ring-shaped support member 35. 34 and a claw-shaped magnetic pole portion 36 integrated with the H.34. A bearing 37 that rotatably holds the rotary shaft 31 is provided at the rear end of the rotary shaft 31.

  The field winding 4 generates a magnetic flux to be supplied to the rotor 3 and is wound around the fixed yoke portion 41. The fixed yoke portion 41 is a cylindrical member and is fixed to the rear housing 52 by a bolt 42. The fixed yoke portion 41 forms a part of the field formed by the rotor 3.

  The front housing 51 and the rear housing 52 support the stator 2 and the rotor 3. The above-described bearing 37 is press-fitted into the rear housing 52 and fixed. Further, the end of the rotating shaft 31 protrudes from the front housing 51, and a cooling fan 53 and a pulley (not shown) are fastened and fixed to the protruding rotating shaft 31 by a nut 54. The regulator 7 adjusts the output voltage of the brushless vehicle AC generator 1 by intermittently supplying the excitation current supplied to the field winding 4.

  Next, the details of the rectifier 6 and the rear cover 8 will be described. FIG. 3 is a plan view of the rectifier 6. FIG. 4 is a bottom view of the rectifier 6. FIG. 5 is a perspective view of the rectifier 6. FIG. 6 is a schematic diagram showing the assembled state of the rectifier 6 and the rear cover 8. As shown in these drawings, the rectifying device 6 includes a positive-side radiating fin 62 and a negative-side radiating fin 63 that are stacked so as to be opposed to each other in the axial direction across the terminal block 61. Six positive-side rectifying elements 64 are press-fitted into six through holes provided in the positive-side radiating fin 62. Similarly, six negative side rectifying elements 65 are press-fitted into six through holes provided in the negative side heat radiation fin 63. Three positive rectifying elements 64 and three negative rectifying elements 65 are combined into a three-phase full-wave rectifier circuit. The rectifier 6 of the present embodiment is provided with two sets of such three-phase full-wave rectifier circuits, and rectifies the output voltage of the stator winding 22 to be output terminals 66 fixed to the positive-side radiation fins 62. The output current is output to the outside.

  Further, the rectifier 6 has three auxiliary diodes 67 that rectify the voltage induced in the stator winding 22 and supply the exciting current to the field winding 4. These auxiliary diodes 67 are attached to the terminal block 61. The terminal block 61 includes a metal terminal 68 that performs necessary electrical wiring for the positive-side rectifying element 64, the negative-side rectifying element 65, and the auxiliary diode 67, and positive-side heat dissipation to the auxiliary diode 67 joined to the terminal 68. It has the partition part 69 which interrupts | blocks the heat radiation from the fin 62 and the negative electrode side radiation fin 63. FIG. The partition wall 69 has a concave shape, and three auxiliary diodes 67 are disposed inside thereof. Accordingly, each auxiliary diode 67 can be disposed at a position on the inner peripheral side of the positive-side radiating fin 62 and the negative-side radiating fin 63 and in which the circumferential positions do not overlap. An intake introduction hole 70 is formed at a location corresponding to the bottom surface of the recess of the partition wall 69.

  The rear cover 8 is for protecting an electrical component composed of the rectifier 6 and the regulator 7, and has a plurality of intake holes 81 for introducing cooling air into the interior (electrical component side), and a cylindrical shape protruding toward the electrical component side. The intake guide wall 83 is formed of, for example, a resin material. The intake air introduction guide wall 83 is for guiding the cooling air introduced into the inside through the intake hole 81 to the plurality of intake air introduction holes 70 of the partition wall portion 69 formed in the terminal block 61 of the rectifying device 6. In addition to the intake holes 81, the rear cover 8 is formed with intake windows for introducing cooling air into the positive-side radiating fins 62 and the negative-side cerebral heat fins 63, but are not shown in FIGS. ing.

  When the cooling fan 53 rotates together with the rotating shaft 31, cooling air is introduced into the inner circumferential space of the intake air introduction guide wall 83 through the intake holes 81 formed in the rear cover 8. This cooling air is further introduced into the inner space of the partition wall 69 through the intake air introduction hole 70 formed in the bottom surface portion of the partition wall 69 of the terminal block 61 of the rectifier 6, and after cooling the auxiliary diode 67, It passes through the portion of the rear housing 52 where the bearing 37 is fixed, and reaches the internal space of the rear housing 52 (the space in which the stator 2 and the rotor 3 are housed).

  FIG. 7 is a diagram showing the results of measuring the temperature of the auxiliary diode 67 and the bearing 37 in the brushless vehicle AC generator 1 of the present embodiment at an ambient temperature of 105 ° C. FIG. In FIG. 7, A shows the temperature in the structure of this embodiment, and B shows the temperature in the conventional structure. As shown in FIG. 7, it was confirmed that the auxiliary diode 67 was reduced by 40 ° C. with respect to the conventional structure, and the bearing 37 was reduced by 5 ° C.

  Thus, in the brushless vehicle AC generator 1 of the present embodiment, attention is paid to the fact that the brush device arranged to cover the end of the rotating shaft 31 of the rotor 3 becomes unnecessary in the case of the brushless structure. By arranging the auxiliary diode 67 in this empty space, it is possible to reduce the temperature of the auxiliary diode 67 by separating the auxiliary diode 67 from the positive-side radiating fin 62 and the negative-side radiating fin 63 of the rectifier 6. That is, by arranging the auxiliary diode 67 at a position that is on the inner peripheral side of the positive-side radiating fin 62 and the negative-side radiating fin 63 and whose circumferential position does not overlap, the positive-side radiating fin 62 and the negative-side radiating fin 63 It becomes possible to prevent the influence of the direct heat damage to the auxiliary diode 67 due to the heat radiation from the surface. Further, it is possible to extend the life of the auxiliary diode 67 due to the temperature reduction.

  Further, by forming the intake hole 81 of the rear cover 8 at a position corresponding to the auxiliary diode 67 along the rotation axis 31 of the rotor 3, it is sucked from the outside of the rear cover 8 and used for cooling other members. It is possible to directly apply the cooling air having a low temperature directly to the auxiliary diode 67 and the bearing 37, so that these temperatures can be surely reduced and the life can be extended.

  In addition, a concave partition wall 69 that blocks heat dissipation from the positive-side radiating fins 62 and the negative-side radiating fins 63 to the auxiliary diode 67 is formed on the terminal block 61 of the rectifying device 6. Is arranged. For this reason, the heat radiation from the positive-side radiating fins 62 and the negative-side radiating fins 63 to the auxiliary diode 67 is surely blocked by the partition wall 69 and the cooling air is guided to the auxiliary diode 67 and the bearing 37 along the partition wall 69. It becomes possible to reliably reduce these temperatures.

  Further, by providing the rear cover 8 with the intake introduction guide wall 83 that guides the cooling air introduced from the outside to the auxiliary diode 67, the rear cover 8 has a low temperature that is sucked from the outside of the rear cover 8 and is not used for cooling other members. Only the cooling air can be separated and directly applied to the auxiliary diode 67 and the bearing 37, and these temperatures can be reliably reduced.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. For example, in the above-described embodiment, the external fan type brushless vehicle AC generator provided with the cooling fan 53 outside the front housing 51 has been described. However, the rotor 3 is provided inside the front housing 51 and the rear housing 52. The present invention may be applied to an internal fan type AC generator for a brushless vehicle provided with a cooling fan. Further, the brushless vehicle AC generator having a structure in which the rear cover 8 is provided separately from the rear housing 52 has been described. However, the present invention is also applied to a structure in which the rear cover is omitted so that the entire electrical component is covered by the rear housing 52. be able to. In this case, the intake introduction guide wall 83 formed in the rear cover 8 may be formed in a part of the rear housing 52.

It is sectional drawing which shows the whole structure of the alternating current generator for brushless vehicles of one Embodiment. It is a rear view which shows the whole structure of the alternating current generator for brushless vehicles of one Embodiment. It is a top view of a rectifier. It is a bottom view of a rectifier. It is a perspective view of a rectifier. It is the schematic which shows the assembly | attachment state of a rectifier and a rear cover. It is a figure which shows the result of having measured the temperature of the auxiliary diode and the bearing in the alternating current generator for brushless vehicles of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Brushless vehicle AC generator 2 Stator 3 Rotor 4 Field winding 6 Rectifier 7 Regulator 8 Rear cover 31 Rotating shaft 37 Bearing 51 Front housing 52 Rear housing 53 Cooling fan 61 Terminal block 62 Positive side radiating fin 63 Negative side Radiation fin 64 Positive-side rectifying element 65 Negative-side rectifying element 67 Auxiliary diode 68 Terminal 69 Bulkhead portion 70 Intake inlet hole 81 Intake hole 83 Intake introduction guide wall

Claims (5)

A stator having a stator winding; a rotor disposed opposite to the inner periphery of the stator; a field winding for generating magnetic flux to be supplied to the rotor; and an output voltage of the stator winding A rectifier having a plurality of rectifying elements that rectify and output to the outside, and an auxiliary diode that rectifies the output voltage of the stator winding and supplies an excitation current to the field winding, and rotation of the rotor In a brushless vehicle alternator comprising a bearing that rotatably holds an end of a shaft, and a rear cover that has a plurality of air intake holes that protect the electrical components including the rectifier and introduce cooling air.
The auxiliary diode is disposed between the bearing and the rear cover along the rotation axis of the rotor ,
The rectifier includes a heat radiation fin to which the rectifier element is joined, a metal terminal that performs electrical wiring of the rectifier element and the auxiliary diode, and a partition portion that blocks heat radiation from the heat radiation fin to the auxiliary diode. An AC generator for a brushless vehicle, comprising: a terminal block formed around the auxiliary diode . In claim 1,
The auxiliary diode for a brushless vehicle according to claim 1, wherein the auxiliary diode is disposed at a position on the inner peripheral side of the heat dissipating fin to which the rectifying element is joined and the circumferential position does not overlap. In claim 1,
Part of the plurality of intake holes is formed at a position corresponding to the auxiliary diode along the rotation axis of the rotor. In any one of Claims 1-3,
The partition wall has a concave shape,
An AC generator for a brushless vehicle, wherein the auxiliary diode is disposed inside the partition wall. In any one of Claims 1-4,
The brushless vehicle AC generator according to claim 1, wherein the rear cover includes an intake air introduction guide wall that guides cooling air introduced from the outside to the auxiliary diode.

Images